Analysis of some pesticides in water samples using solid-phase microextraction-gas chromatography with different mass spectrometric techniques

A solid-phase microextraction (SPME)-GC procedure has been developed for th e analysis of four selected pesticides (propanil, acetochlor, myclobutanil and fenoxycarb) in water samples. Mass spectrometry (MS) was used and two d ifferent instruments, a quadrupole MS system and an ion trap operating in t he MS-MS mode, were compared. A Carbowax-divinylbenzene SPME fiber was used . The performances of the two GC-MS instruments were comparable in terms of linearity (in the range of 0.1-10 mu g/l in water samples) and sensitivity (limits of detection were in the low ng/l range); the quadrupole MS instru ment gave better precision than the ion trap MS-MS system, but generally th e relative standard deviations for replicates were acceptable for both inst ruments (<15%). Specificity with these two instruments was comparable in th e analysis of ground water samples. Recovery tests were made to assess the applicability of the SPME procedure in the quantitative analysis of contami nated groundwaters. (C) 1999 Elsevier Science B.V. All rights reserved.